As a believer of Austrian free-market economics, it is my belief that the main purpose of registration [of any property] is to address the inherent problem brought by economic scarcity of goods. It is to establish who owns what. Registration is an issue related to private property. May it be real estate, cars, business or guns.
Gun registration is never been peculiar with any other property in society. The registration of it must only be a matter of economic principle. And matters concerning safety is of secondary concern, or better yet not relevant at all.
Registered or not, gun can always be used as a means to harm others. So as cars, registered or not; driver with or without license, can cause harm to others if one intends to do so [or when an accident occurs]. Registration never change the intent to harm if such intent exists and pursued.
When people use guns to kill or harm anyone, they did not actually chose guns. What they did was have the easiest means available for them carry out their intent. At early times when metallurgy doesn't yet exist, the easiest means to kill anyone is rope, a hard piece of wood, stones etc. and not guns (obviously because gun was yet to exist).
When safety is the issue, gun registration hardly matters. If safety is the main concern, why not push for a system that maximizes every citizen's chance to have defense for himself or his family?.
Only a stupid robber would rob a bus full of citizens with guns. But since the robber is intelligent, he would then look for victims who are less armed and away from the police, who at most cases always late to arrive at crime scenes.